What's the preferred way of offering help with infrastructure problems, and to what extent, in your opinion, is the solution to have more hands on deck vs. farming out certain (groups of) services to different machines?
With the current installations, there aren't that many issues. The one service that could always use more people to help is the roundup installation; in many cases, this involves extending roundup (through the builtin extension mechanisms). Unfortunately, nearly everybody who ever offered to help with the roundup installation ran away after a month or so.
We have most services centralized at xs4all, with a fairly clear separation between mail on the one side, and web on the other side. For the bug tracker, we use a service offered by Upfront Hosting. This takes care of hardware issues and software installation, but we still manage the tracker installation(s).
We recently also had a shortage of people managing email; fortunately, new (active) volunteers were found. For the web content, there is currently nobody really in charge, it seems, which is usually not an issue (my impression is that Aahz and Skip try to see that important things get done). For the Wiki, there is an active group of despammers. The job board has active maintainers again as well.
The various other services don't need steady attention. In particular wrt. software installation, it all works fine - IMO also due to the policy that we use vendor packages if at all possible.
P.S. I might have left out important activities. Please do let me know in private which these are - I might honestly not know, or forgotten how much day-to-day work they actually cost.